Aryl-substituted pyrimidines as insecticidal and acaricidal agents

ABSTRACT

There are provided compositions and methods comprising compounds of formula I: ##STR1## wherein R 1 , A, B, X, Y and Z have the meaning given in claim 1, for the control of insect and acarid pests.

This is a divisional of copending application(s) Ser. No. 09/036,490filed on Mar. 6, 1998, the entire disclosure of which is herebyincorporated by reference.

BACKGROUND OF THE INVENTION

Insect and acarid pests destroy growing and harvested crops. In theUnites States, agronomic crops must compete with thousands of thosepests. In particular, tobacco budworms and southern armyworms areespecially devastating to crops.

Tobacco budworms cause tremendous economic losses in agronomic crops. Inparticular, budworms devastate cotton crops by feeding on green bolls.Control of budworms is complicated by their resistance to many commoninsecticides, including organophosphates, carbamates and pyrethroids.

In spite of the commercial insecticides and acaricides available today,damage to crops, both growing and harvested, caused by insect and acaridpests still occurs. Accordingly, there is ongoing research to create newand more effective insecticidal and acaricidal agents.

Certain pyrimidine compounds are known to possess insecticidal andnematocidal activity (see, e.g., EP 0 506 270). However, none of thosecompounds are within the scope of the present invention.

It is, therefore, an object of the present invention to providecompounds which are highly effective for the control of insect andacarid pests.

It is also an object of the present invention to provide a method forthe control of insect and acarid pests.

It is a further object of this invention to provide a method for theprotection of growing and harvested crops from damage caused by insectand acarid attack and infestation.

Those and other objects of the present invention will become moreapparent from the detailed description thereof set forth below.

SUMMARY OF THE INVENTION

The present invention describes aryl pyrimidines which are useful asinsecticidal and acaricidal agents. Those compounds are also useful forprotecting plants from damage caused by insect and acarid attack andinfestation.

The aryl pyrimidines used according to the present invention have thestructural formula I ##STR2## wherein A and B each independentlyrepresent an optionally substituted aryl group;

R¹ represents a hydrogen or halogen atom or an optionally substitutedalkyl, alkenyl, alkinyl, alkoxy, alkoxyalkyl, alkoxyalkoxy group; or analkylthio group, alkylsulphinyl or alkylsulphonyl group, an amino,alkylamino or dialkylamino group or a cyano, nitro, haloalkyl,haloalkoxy, haloalkylthio or SF5 group, one of Y and Z represents N andthe other; represents CR², in which R² has the meaning given for R¹ ;

X represents O or NR, in which R represents a hydrogen atom or an alkylgroup.

This invention also describes compositions containing those compoundsand methods for using those compounds and compositions. Advantageously,it has been found that the pyrimidine compounds of the presentinvention, and compositions containing them, are useful for the controlof insect and acarid pests. The compounds of this invention are alsouseful for the protection of plants from damage caused by insect andacarid attack and infestation. The pyrimidine compounds are especiallyuseful for the control of tobacco budworms and southern armyworms.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a method for the control of insect oracarid pests which comprises contacting said pests or their food supply,habitat or breeding grounds with a pesticidally effective amount of anaryl pyrimidine of formula I.

The present invention also provides a method for the protection ofgrowing plants from attack or infestation by insect or acarid pestswhich comprises applying to the foliage of the plants, or to the soil orwater in which they are growing, a pesticidally effective amount of anaryl pyrimidine compound of formula I.

The aryl pyrimidines of the present invention have the structuralformula I ##STR3## wherein A, B, X, Y, Z and R¹ are as describedhereinabove for formula I.

Exemplary of halogen hereinabove are fluorine, chlorine, bromine andiodine.

Preferred formula I aryl pyrimidines of the present invention are thosewherein

A and B are each independently phenyl optionally substituted with anycombination of from one to three halogen, C₁ -C₄ alkyl, C₁ -C₄haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups;

R¹ and R² are each independently hydrogen, C₁ -C₄ alkyl, C₁ -C₄ alkoxy,C₁ -C₄ alkylthio, cyano, nitro, amino, C₁ -C₄ haloalkyl, C₁ -C₄haloalkoxy or fluorine; and

A is phenyl optionally substituted with any combination of from one tofive halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄haloalkoxy groups,

B is phenyl optionally substituted with any combination of from one tothree halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy or C₁ -C₄haloalkoxy groups.

More preferred insecticidal and acaricidal agents of the presentinvention are those wherein

A is phenyl optionally substituted with any combination of from one tothree halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ alkoxy, C₁ -C₄alkylthio or C₁ -C₄ haloalkoxy groups;

R¹ and R² each independently are hydrogen, methyl ethyl, fluoro, chloro,cyano, nitro, amino, thiomethyl or trifluoromethyl;

preferably at least one of R¹ and R² is hydrogen; and

A and B are each independently phenyl optionally substituted with anycombination of from one to five halogen, C₁ -C₄ alkyl, C₁ -C₄ haloalkyl,C₁ -C₄ alkoxy or C₁ -C₄ haloalkoxy groups.

The terms "C₁ -C₄ haloalkyl" and "C₁ -C₄ haloalkoxy" are defined as a C₁-C₄ alkyl group and a C₁ -C₄ alkoxy group substituted with one or morehalogen atoms, respectively.

Formula I compounds of this invention which are particularly effectiveinsecticidal agents include the novel compounds of formulae IA and IB:##STR4## R¹ and R² each independently represents a hydrogen or halogenatom or an alkyl, alkenyl, alkinyl, alkoxy, alkoxyalkyl, alkoxyalkoxygroup, alkylthio, alkylsulphinyl or alkylsulphonyl group, an amino,alkylamino or dialkylamino group or a cyano, nitro, haloalkyl,haloalkoxy, haloalkylthio or SF₅ group,

A represents a phenyl group being substituted by one or more of the sameor different substituents selected from halogen atoms, alkyl, alkoxy,cyano, nitro, haloalkyl, haloalkoxy, alkylthio, haloalkylthio,alkylsulphinyl, alkylsulphonyl and SF₅ groups; and

B represents a phenyl group being substituted by one or more of the sameor different substituents selected from halogen atoms, alkyl, alkoxy,cyano, nitro, haloalkyl, haloalkoxy, alkylthio, haloalkylthio,alkylsulphinyl, alkylsulphonyl and SF₅ groups; ##STR5## wherein R¹ andR² have the meaning given in claim 1; A represents a phenyl group beingsubstituted by one or more of the same or different substituentsselected from halogen atoms, alkyl, alkoxy, cyano, nitro, haloalkyl,haloalkoxy, alkylthio, haloalkylthio, alkylsulphinyl, alkylsulphonyl andSF₅ groups; and

B represents a phenyl group being substituted by one or more of the sameor different substituents selected from halogen atoms, alkyl, alkoxy,cyano, nitro, haloalkyl, haloalkoxy, alkylthio, haloalkylthio,alkylsulphinyl, alkylsulphonyl and SF₅ groups.

Particularly preferred are the compounds of formulae IA1 and IA2##STR6## in which R¹ and R² have the meaning given for formulae IA andIB; and

R³ through R⁸ each independently represent a hydrogen or halogen atom,in particular F or Cl, or a C₁₋₄ alkyl, in particular methyl or ethyl, aC₁₋₄ alkoxy, in particular methoxy or ethoxy, a C₁₋₄ haloalkyl, inparticular trifluoromethyl, a C₁₋₄ haloalkoxy, in particular difluoro-or trifluoromethoxy, a cyano or nitro group.

Preferably at least one of the groups R³, R⁴ and R⁵ is different from ahydrogen atom and at least one of the groups R⁶, R⁷ and R⁸ is differentfrom a hydrogen atom.

Advantageously, it has been found that the formula I compounds of thepresent invention are especially useful for the control of tobaccobudworms and southern armyworms.

Aryl pyrimidines of the present invention wherein Y is CR¹ and Z is N(formula IA) may be prepared by reacting a compound of formula IIA##STR7## in which B, R¹ and R² have the meaning given and L¹ is aleaving group, with a compound of general formula IIIA,

    A--OM.sup.1                                                IIIA

wherein

A is defined as for formula IA; and

M¹ represents a hydrogen or a metal atom.

Furthermore, the invention relates to a process for the preparation of acompound of general formula IB, which comprises reacting a respectivecompound of the general formula IIB, ##STR8## in which B, R¹ and R² havethe meaning given and L¹ is a leaving group, with a compound of generalformula IIIA,

    A--OM.sup.1                                                IIIA

wherein

A is defined as for formula IB; and

M¹ represents a hydrogen or metal atom.

Advantageously, certain formula I compounds of this invention may bederivatized by conventional procedures known in the art to produce othercompounds of formula I.

The aryl pyrimidine compounds of the present invention are effective forcontrolling insect and acarid pests. Those compounds are also effectivefor protecting growing or harvested crops from damage caused by insectand acarid attack and infestation.

Insects controlled by the aryl pyrimidine compounds of this inventioninclude Lepidoptera such as tobacco budworms, cabbage loopers, cottonboll worms, beet armyworms, southern armyworms and diamondback moths;Homoptera such as aphids, leaf hoppers, plant hoppers and white flies;Thysanoptera such as thrips; Coleoptera such as boll weevils, Coloradopotato beetles, southern corn rootworms, western corn rootworms andmustard beetles; and Orthoptera such as locusts, crickets, grasshoppersand cockroaches. Acarina controlled by the compounds of this inventioninclude mites such as two-spotted spider mites, carmine spider mites,banks grass mites, strawberry mites, citrus rust mites and leprosismites. Advantageously, it has been found that the compounds of thepresent invention are especially effective against tobacco budworms andsouthern armyworms.

In practice generally about 10 ppm to about 10,000 ppm and preferablyabout 100 ppm to about 5,000 ppm of a formula I aryl pyrimidine,dispersed in water or another liquid carrier, is effective when appliedto plants or the soil in which the plants are growing to protect theplants from insect and acarid attack and infestation.

The aryl pyrimidine compounds of this invention are also effective forcontrolling insect and acarid pests when applied to the foliage ofplants and/or to the soil or water in which said plants are growing insufficient amount to provide a rate of about 0.1 kg/ha to 4.0 kg/ha ofactive ingredient.

While the compounds of this invention are effective for controllinginsect and acarid pests when employed alone, they may also be used incombination with other biological chemicals, including otherinsecticides and acaricides. For example, the formula I compounds ofthis invention may be used effectively in conjunction or combinationwith pyrethroids, phosphates, carbamates, cyclodienes, endotoxin ofbacillus thuringiensis (Bt), formamidines, phenol tin compounds,chlorinated hydrocarbons, benzoylphenyl ureas, pyrroles and the like.

The compounds of this invention may be formulated as emulsifiableconcentrates, flowable concentrates or wettable powders which arediluted with water or other suitable polar solvent, generally in situ,and then applied as a dilute spray. Said compounds may also beformulated in dry compacted granules, granular formulations, dusts, dustconcentrates, suspension concentrates, microemulsions and the like allof which lend themselves to seed, soil, water and/or foliageapplications to provide the requisite plant protection. Suchformulations include the compounds of the invention admixed withagronomically acceptable inert, solid or liquid carriers.

In order to facilitate a further understanding of the invention, thefollowing examples are presented primarily for the purpose ofillustrating more specific details thereof. The invention should not bedeemed limited by the examples as the full scope of the invention isdefined in the claims.

EXAMPLE 1 1A Preparation of 4-(3,4-dichlorophenyl)-2-chloropyrimidine(METHOD A)

To a 1L 3-neck flask fitted with an addition funnel, N₂ inlet, magneticstir bar and thermometer was added 15.26 (0.067 mol) of3,4-dichlorobromobenzene in 50-75 mL of anhydrous ether. The reactionwas cooled to -90° C. and 96 mL of tertbutyllithium (1.7 M solution inpentane) slowly was added over a 0.5 hr while maintaining thetemperature below -70° C. The reaction temperature was cooled to -80 to-90° C. and 2-chloropyrimidine (9.10 gm, 0.08 mol) dissolved inanhydrous THF was added. The reaction was stirred for about 2 h and 18gms of DDQ, (0.077 mol) dissolved in anhydrous THF was added slowly, andthe mixture was stirred for a 0.5 h. Three mL of H₂ O containing 1 mL ofHOAc in THF was added and the mixture stirred for 15 minutes. Thereaction was diluted with 100 mL of H₂ O and 100 mL of EtOAc and themixture transferred to a separatory funnel. The organic layer wasseparated, dried, filtered and evaporated. The crude product waschromatographed and eluted with 30% EtOAc/heptane and triturated withEt₂ O to yield 3.22 g of a white solid (20%) m.p. 126-127° C.

1B Preparation of4-(3,4-dichlorophenyl)-2-(3-trifluoromethylphenoxy)-pyrimidine

A 100 mL flask was charged with 1.2 g of 1A and the solid was dissolvedin 8 mL of 8% trimethylamine/toluene solution and stirred overnight atroom temperature. The resulting solid was collected by vacuum filtrationto produce a quantitative yield of the trimethylammonium hydrochloridesalt. (m.p. 179° C.) A 100 mL flask was charged 0.44 g (0.002 mol) ofthe salt, 0.26 g (1.25 eq) of K₂ CO₃ and 5 mL of DMF and stirred for 15min at RT. 0.25 g (1.1 eq) of m-trifluoromethyl-phenol was added and thereaction allowed to stir 36 h. The reaction was diluted with 5 mL of H₂O and 10 mL of EtOAc, transferred to separatory funnel and the organiclayer was washed sequentially with 10 mL 10% NaOH and 10 mL of 10% HCl.The organic layer was dried (Na₂ SO₄), filtered and evaporated to yieldan oil. The crude product was chromatographed on silica gel and elutedwith 20% EtOAc/heptane. The white solid was triturated in heptane toyield 0.26 g of white solid (45%, m.p. 106-106.5° C.).

EXAMPLE 2 Preparation of2-(3-trifluoromethyl-4-fluorophenoxy)-4-(4-fluorophenyl)pyrimidine(METHOD B)

2A Preparation of 4-fluoroacetocyanoimine 10.4 g (75 mmol) of4-fluoroacetophenone was converted to 2A by the procedure of Aumullerand Hunig, (Angew, Chem. Int.Ed. 23 (1974) 447-448). The crude reactionmixture was poured onto 1.5 L of crushed ice and the organic layerremoved. The aqueous phase was re-extracted with 100 mL of CH₂ Cl₂ andthe combined organic phases washed with 50 mL water, dried (MgSO₄),filtered and evaporated to give 8.2 g (67%) of a white solid (m.p.100-106° C.) which was sufficiently pure to use in the next step.

2B Preparation of 4-(4-fluorophenyl)-2-chloropyrimidine

To a solution of 6.0 g of 2A in 150 mL of CH₂ Cl₂ 15.5 g (155 mmoles) ofphosphorous oxychloride and 5.95 g of DMF was added over 5 minutes. Theresulting mixture is stirred at room temperature for 18 h, then quenchedslowly with 50 mL of H₂ O. The reaction mixture was transferred to aseparatory funnel. The aqueous phase was extracted with 50 mL of CH₂ Cl₂and the combined organic phases washed sequentially with 50 mL H₂ O and50 mL brine, dried, filtered and evaporated to a yellow solid. The crudeproduct was purified by silica gel chromatography and eluted with 7/3heptane/ethyl acetate to yield 1.24 g white solid. Re-crystallization ofimpure fractions yielded an additional 0.32 g of white crystallinesolid. (m.p. 122-128° C.; 20%).

2C Preparation of4-(4-fluorophenyl)-2-(4-fluoro-3-trifluoromethylphenoxy)-pyrimidine

To a solution of 0.60 g (2.87 mmol) of 2B in 15 ml of dimethylformamidewas added 0.46 g of K₂ CO₃ (3.3 mmol) and 0.60 g (3.3 mmol) of4-fluoro-3-trifluoromethyl-phenol and the resulting mixture heated at50° C. for 15 hr and 75° C. for 24 hrs. The cooled reaction mixture waspoured into a separatory funnel containing 100 mL of ethyl acetate andwashed with 2×50 mL water, 3×15 mL 2.5% NaOH solution, 1×30 mL brine,dried and evaporated in vacuuo to yield 1.95 g of a mobile yellowliquid. This material was filtered through a pad of silica andre-crystallized from heptane/ethyl acetate to give 0.49 g whitecrystalline solid (m.p. 69-74° C.; 48%).

EXAMPLE 3 Preparation of2-(3-trifluoromethyl-4-fluorophenoxy)-4-(3,4-dichlorophenyl)-5-chloropyrimidine(Method C)

3A Preparation of 2,4,5-trichloropyrimidine

10 g (0.068 mol) of 5-chlorouracil in 20 mL POCl₃ (0.21 mol) was treatedwith 18 mL of N,N-diethylaniline (0.14 mol) at ambient temperature. Thestirred mixture was heated to 100° C. for 4 h. Volatile solvents wereremoved in vacuo and the residue dissolved in 100 mL of diethyl etherand washed with 2×100 mL of ice cold 10% HCl solution, dried, filteredand evaporated to yield 8.54 g (82.9%) of 2,4,5-trichloropyrimidine as acolorless liquid. b.p. 73-75° C./3 Torr).

3B Preparation of 2,5-dichloro-4-(3,4-dichlorophenyl)pyrimidine

A suspension of 0.19 g (0.5 mmol) of bis(benzonitril)dichloro-palladium(II) and 0.2 g 1,4-bis(diphenylphosphino)butane in 10 mL of toluene washeated at reflux with stirring for 1 h under nitrogen. The suspensionwas cooled to room temperature. One gram (6.6 mmol) of 3A, 1.57 g of3,4-dichlorobenzene boronic acid (8.2 mmol), 2.5 mL EtOH and 5 mL of 1 MNa₂ CO₃ were added and the mixture heated to reflux for 20 h. Thereaction mixture was cooled and diluted with 100 mL Et₂ O. Thesuspension was filtered through a plug of silica gel and the cake washedwith an additional 100 mL of Et₂ O. The ether was evaporated and theresidue chromatographed over silica gel (10% EtOAc/hexane). A fractioncontaining 0.72 g (32%) of 2,5-dichloro-4-(3,4-dichlorophenyl)pyrimidinewas isolated as a white solid. (m.p. 125-126° C.)

3C Preparation of2-(3-trifluoromethyl-4-fluorophenoxy)-4-(3,4-dichlorophenyl)-5-chloropyrimidine

To a solution of 0.5 g (1.7 mmol) of 3B in 10 mL of toluene was added4.0 mL of 10% trimethylamine/toluene solution and the mixture stirred atroom temperature for 20 min. To the resulting mixture was added 0.36 g(20 mmol) of 3-trifluoromethyl-4-fluorophenol and the mixture stirredovernight. The reaction mixture was diluted with H₂ O and transferred toa separatory funnel and extracted with 40 mL of methylene chloride. Theorganic layer was washed sequentially with 5% NaHCO₃ solution and water,dried and evaporated to yield 0.52 g (70.3%) of2-(3-trifluoromethyl-4-fluorophenoxy)-4-(3,4-dichlorophenyl)-5-chloropyrimidine(m.p. 90-92)

EXAMPLE 4 Preparation of2-(3-trifluoromethyl-4-fluorophenoxy)-4-(3,4-dichlorophenyl)-6-trifluoromethylpyrimidine (METHOD D)

4A Preparation of2-chloro-4-(3,4-dichlorophenyl)-6-trifluoromethylpyrimidine

4A was prepared from 2-chloro-4-trifluoromethylpyrimidine and3,4-dichlorobromobenzene by the method reported for 1A. (Method A) ¹ HNMR 1H,(8.29,8.28,d) 1H,(8.01,8.00,7.98,7.97,dd) 1H, (7.92,s)1H,(7.66,7.63,d).

4B Preparation of2-m-trifluoromethylphenoxy-4-(3,4-dichlorophenyl)-6-trifluoromethylpyrimidine

4B was prepared from 4A as described for 1B. (Method A). This yielded0.28 g of 4B m.p. 111-112° C.

EXAMPLE 5 Preparation of2-(3-trifluoromethyl-4-fluorophenoxy)-4-(4-chlorophenyl)-6-cyanopyrimidine

5A Preparation of 2-thiomethyl-4-(4-chlorophenyl)-6-chloro-pyrimidine

5A is prepared from 2-thiomethyl-4-chloropyrimidine and4-chlorobromobenzene by the method reported for 1A: ¹ H NMR:2H(8.02,8.00,d), 2H (7.48, 7.46,d), 1H(7.34,s)

5B Preparation of 2-Thiomethyl-4-(4-chlorophenyl)-6-cyano-pyrimidine

A solution of 1.5 g of 5A and 20 mL of an 8% solution of trimethylaminein toluene was stirred over night. The mixture was triturated withtoluene, filtered to yield 2.08 g of the trimethylammonium salt: ¹ H NMR1H(9.27,s), 2H(8.61,8.59,d), 2H (7.54,7.52,d), 9H(4.11,s), 3H(2.69,s).To a solution of 1.0 g (3 mmol) of the ammonium salt in 10 mL of CH₂ Cl₂was added 0.47 g (3 mmol) of tetraethylammonium cyanide and the solutionwas stirred for 30 min. The solution was transferred to a separatoryfunnel and washed sequentially with 20 mL of H₂ O and 10 mL of brine,dried, filtered and evaporated to yield 0.46 g (48%) 5B: ¹ H NMR2H(8.06,8.03,d), 1H(7.63,s), 2H(7.52,7.50,d), 3H(2.64,s)

5C2-(3-Trifluoromethyl-4-fluorophenoxy)-4-(4-chlorophenyl)-6-cyanopyrimidine

A solution of 0.54 g (2 mmol) of 5B, 0.72 g (2.0 eq) of MCPBA and 20 mLof CH₂ Cl₂ was heated at reflux for 1 h, cooled to room temperature andtransferred to a separatory funnel. The solution was washed with 10%NaHCO₃, dried (Na₂ SO₄), filtered and evaporated to yield 0.27 g of thesulfoxide: ¹ H NMR: 1H(8.18,s) 2H(8.185,8.16,d), 2H (7.59,7.57,d), 3H(3.46,s). A solution of 0.135 g (0.5 mmol) of the sulfoxide, 0.15 g (3eq) of Na₂ CO₃, 0.09 g (1.1 eq) of 3-trifluoromethyl-4-fluorophenol and5 mL of DMF were stirred for overnight at room temperature, heated to60° C. for 4 h then cooled to room temperature. The resulting solutionwas diluted with 10 mL of EtOAc and washed sequentially with 10 mL of10% NaOH and 10% HCl, dried, filtered and evaporated. The crude productwas adsorbed on silica gel and 5C eluted with 20% EtOAc/hexane to yield0.12 g of white solid, m.p. 131-132° C.

EXAMPLE 6 Preparation of2-(3-trifluoromethyl-4-fluorophenoxy)-4-(3,4-dichlorophenyl)-6-methylthio-pyrimidineand2-(3-trifluoromethyl-4-fluorophenoxy)-4-(3,4-dichlorophenyl)-6-methylsulfonylpyrimidine

6A Preparation of 4-(3,4-chlorophenyl)-2,6-dichloropyrimidine

Prepared from 2,4-dichloropyrimidine and 3,4-dichlorobromobenzene by themethod reported for 1A: ¹ H NMR; 1H (8.21, 8.20, d) 1H (7.93, 7.92,7.90, 7.89, dd), 1H (7.65, s), 1H (7.62, 7.59, dd)

6B 2-chloro-4-(3,4-dichlorophenyl)-6-thiomethyl-4-pyrimidine

To a solution of 0.61 gm (2 mmol.) of 6A and 5 mL of dioxane was added0.14 g (2 mmol) of NaSMe and the resulting solution was stirred at roomtemperature for 72 h. The reaction mixture was diluted with EtOAc andwashed with 10 mL of H₂ O, dried over Na₂ SO₄, filtered and evaporated,then triturated with ether. The solid was collected by filtration toyield 0.30 g 6B: ¹ H NMR, 1H (8.156, 8.151,d),1H(7.87,7.86,7.85,7.84,dd), 1H(7.57,7.55,d), 1H(7.42,s), 3H(2.63,s)

6C Preparation of2-(3-trifluoromethyl-4-fluorophenoxy)-4-(3,4-dichlorophenyl)-6-thiomethylpyrimidine

6B was converted to the trimethylammonium salt and subsequently reactedwith 3-trifluoromethyl-4-fluorophenol by the procedure described for 1Bto yield 0.19 g of 6C: m.p. 104-105° C., (54%).

6D Preparation of2-(3-trifluoromethyl-4-fluorophenoxy)-4-(3,4-dichlorophenyl)-6-methylsulfonyl-4-arylpyrimidine

6C was converted to 6D by oxidation with MCPBA as described for 5C. Thereaction yielded 0.41 g (91%) of white solid 6D m.p. 137-138° C.

EXAMPLE 7 Preparation of6-amino-2-(3-trifluoromethyl-4-fluoro)aryloxy-4-aryl pyrimidine

7A Preparation of2-thiomethyl-4-chloro-6-tertbutoxycarbonylaminopyrimidine

A solution of 5.06 g (0.03 mol.) of4-amino-6-chloro-2-(methylthio)pyrimidine, 9 mL (2 eq) of Et₃ N, 6.9 g(0.03 mol) of di-tert-butyl-dicarbonate and 20 mL of THF was refluxedfor 2 days. The reaction was cooled to room temperature, evaporated andthe residue adsorbed on silica gel and eluted with 10% EtOAc/heptane toyield 5.86 g (74%) of the protected amine: ¹ H NMR, 1H (7.64,s),1H(7.28,broad s), 3H(2.50), 9H(1.52,s)

7B Preparation of 6-NH-Boc-2-thiomethyl-4-(3,4-dichlorophenyl)pyrimidine

A round bottom flask was charged with 0.21 g (0.5 mmol.) ofbis(benzonitrile)dichloro palladium, 0.23 g (0.5 mmol.) of bis(diphenylphosphorus)butane in 10 mL of toluene and refluxed for 2 h. The solutionwas cooled to room temperature and and 1.3 g of 3,4-dichlorophenylboronic acid, 1.5 g of 7A, 5 mL 1M Na₂ CO₃ and 20 mL of EtOH were addedand the solution was refluxed for an additional 2 h. The reactionmixture was cooled to room temperature. On standing overnight the asolid precipitated which was filtered and discarded. The mother liquorwas concentrated and on standing formed a solid that was triturated withheptane. The solid was filtered to yield 1.19 gm (57%) of white solid:m.p. 158-159° C.

7C Preparation of6-NH-Boc-2-methylsulfonyl-4-(3,4-dichlorophenyl)pyrimidine

Prepared by the as described for 6D :m.p. 185-186° C.

7D Preparation of6-amino-2-(3-trifluoromethylphenoxy)-4-(3,4-dichlorophenyl)pyrimidine

A round-bottom flask was charged with 0.73 g of 7C, 15 mL of DMF and0.55 g (3 eq.) of Na₂ CO₃ and stirred for 15 m. To the solution wasadded 0.31 g (1.1 eq) of 3-trifluoromethylphenol and the mixture heatedto reflux for 4 h, cooled and allowed to stand overnight. The solutionwas diluted with 10 mL of water and transferred to a separatory funneland washed with 30 mL of EtOAc. The organic layer was sequentiallywashed with 10 mL of 10% NaOH, 10% HCl, dried, filtered and evaporated.The crude product was absorbed on silica gel and eluted with 50%EtOAc/heptane

7E Preparation of6-methyl-2-(3-trifluoromethyl-4-fluorophenoxy)-4-(3,4-dichlorophenyl)Prepared by the procedure described for 7D utilizing4-methyl-6-chloro-2-(methylthio)pyrimidine as the starting material

EXAMPLE 8 Preparation of2-[N-methyl-N-(4-fluoro-3-trifluoromethylphenyl)amino]-4-(4-fluoro-3-trifluoromethylphenyl)-pyrimidine(METHOD E)

A round-bottom flask was charged with 1.03 g of2-chloro-4-(4-fluoro-3-trifluoromethylphenyl)-pyrimidine and 0.82 g of4-fluoro-3-trifluoromethyl-N-methylaniline and heated to 126° C. for 1.5h. The reaction mixture melted and subsequently thickened. Afterstanding overnight, the mixture was partitioned between 20 mL of EtOAcand 20 mL of NaHCO3. The organic phase was separated, dried, filteredand evaporated. The crude product was adsorbed onto silica gel andeluted with 50% EtOAc/heptane to yield 0.67 g of an oil which solidifiedon standing: m.p. 83-84° C.

EXAMPLE 9 Preparation of4-methyl-5-phenyl-3-(3-trifluoromethylphenoxy)-pyrimidine

9A Preparation of 2-Amino-1-methyl-2-phenylacrylonitrile

A round-bottom flask was charged with 7.2 g of 1-benzoylpropionitrile,200 ml of ethanol and 10.0 g of ammonium acetate and heated to refluxfor 1.5 h. Ethanol was distilled off. The residue was diluted with 200ml of EtOAc and washed with 100 mL of H₂ O twice, dried over MgSO₄,filtered and evaporated. The product was obtained as an amber oil (7.15g) which solidified on standing (m.p. 68-86° C.).

9B Preparation of 2-chloro-4-methyl-5-phenylpyrimidine

A round-bottom flask was charged with 1.5 g of crude 9A, 1.8 ml ofphosphorous oxychloride, 1.5 ml of dimethylformamide and 30 ml ofacetonitrile and stirred for 30 minutes at 30° C. and subsequentlyheated to reflux for 6.5 h. The reaction was diluted with 150 ml ofEtOAc and washed with 50 mL of H₂ O twice, dried over MgSO₄, filteredand evaporated. The crude product was adsorbed onto silica gel andeluted with 50% EtOAc/heptane to yield 0.61 g of a yellow liquid.

9C Preparation of4-(4-fluorophenyl)-2-(4-fluoro-3-trifluorophenoxy)-pyrimidine

To a solution of 0.61 g of 9B in 30 ml of dimethylformamide was added0.5 g of K₂ CO₃ and 0.58 g of 3-trifluoromethylphenol and the resultingmixture was heated at 60° C. for 15 hr and 75° C. for 24 h. The cooledreaction mixture was poured into a separatory funnel containing 100 mLof ethyl acetate and washed with 2×50 mL water, 3×15mL 2.5% NaOHsolution, 1×30 mL brine, dried and evaporated in vacuuo to yield 0.93 gof a yellow oil.

Using essentially the same procedure, the compounds given in tables I toIII are obtained:

                  TABLE I                                                         ______________________________________                                         ##STR9##                                                                     Compound                                                                      No.     R.sup.3                                                                              R.sup.4                                                                              R.sup.5                                                                            R.sup.6                                                                            R.sup.7                                                                            R.sup.8                                                                            X    Method                         ______________________________________                                         1      CF.sub.3                                                                             Cl     H    H    Cl   H    O    A                               2      CF.sub.3                                                                             H      H    H    Cl   H    O    A                               3      CF.sub.3                                                                             NO.sub.2                                                                             H    H    Cl   H    O    A                               4      CF.sub.3                                                                             F      H    H    Cl   H    O    A                               5      CF.sub.3                                                                             H      H    H    H    H    O    A                               6      CF.sub.3                                                                             F      H    H    H    H    O    A                               7      Cl     CF.sub.3                                                                             H    H    H    H    O    A                               8      CF.sub.3                                                                             NO.sub.2                                                                             H    H    H    H    O    A                               9      CF.sub.3                                                                             H      H    H    NO.sub.2                                                                           H    O    B                              10      CF.sub.3                                                                             F      H    H    NO.sub.2                                                                           H    O    B                              11      CF.sub.3                                                                             NO.sub.2                                                                             H    H    Et   H    O    A                              12      Cl     Cl     H    H    Et   H    O    A                              13      Cl     F      H    H    Et   H    O    A                              14      CF.sub.3                                                                             F      H    H    Et   H    O    A                              15      CF.sub.3                                                                             H      H    H    Et   H    O    A                              16      CF.sub.3                                                                             F      H    H    Et   H    NH   A                              17      CF.sub.3                                                                             Cl     H    H    Et   H    O    A                              18      Cl     Cl     H    H    H    CF.sub.3                                                                           O    A                              19      CF.sub.3                                                                             NO.sub.2                                                                             H    H    H    CF.sub.3                                                                           O    A                              20      Cl     Cl     H    H    H    CF.sub.3                                                                           O    A                              21      CF.sub.3                                                                             F      H    H    H    CF.sub.3                                                                           O    A                              22      CF.sub.3                                                                             F      H    H    F    H    O    B                              23      CF.sub.3                                                                             H      H    H    F    H    O    B                              24      CF.sub.3                                                                             F      H    H    t-Bu H    O    A                              25      CF.sub.3                                                                             Cl     H    H    t-Bu H    O    A                              26      CF.sub.3                                                                             NO.sub.2                                                                             H    H    t-Bu H    O    A                              27      Cl     Cl     H    H    t-Bu H    O    A                              28      Cl     Cl     H    H    CF.sub.3                                                                           H    O    A                              29      CF.sub.3                                                                             F      H    H    CF.sub.3                                                                           H    O    A                              30      CF.sub.3                                                                             H      H    H    CF.sub.3                                                                           H    O    A                              31      Cl     F      H    H    CF.sub.3                                                                           H    O    A                              32      CF.sub.3                                                                             Cl     H    H    CF.sub.3                                                                           H    O    A                              33      CF.sub.3                                                                             NO.sub.2                                                                             H    H    CF.sub.3                                                                           H    O    A                              34      CF.sub.3                                                                             F      H    H    MeO  H    O    A                              35      CF.sub.3                                                                             Cl     H    H    MeO  H    O    A                              36      CF.sub.3                                                                             H      H    H    MeO  H    O    A                              37      CF.sub.3                                                                             F      H    H    H    OCF.sub.3                                                                          O    A                              38      CF.sub.3                                                                             H      H    H    H    OCF.sub.3                                                                          O    A                              39      CF.sub.3                                                                             Cl     H    H    H    OCF.sub.3                                                                          O    A                              40      CF.sub.3                                                                             NO.sub.2                                                                             H    H    H    OCF.sub.3                                                                          O    A                              41      Cl     H      Cl   H    H    OCF.sub.3                                                                          O    A                              42      CF.sub.3                                                                             H      CF.sub.3                                                                           H    H    OCF.sub.3                                                                          O    A                              43      Cl     Cl     H    H    H    OCF.sub.3                                                                          O    A                              44      Cl     H      Cl   H    OCF.sub.3                                                                          H    O    A                              45      CF.sub.3                                                                             H      CF.sub.3                                                                           H    OCF.sub.3                                                                          H    O    A                              46      CF.sub.3                                                                             Cl     H    H    OCF.sub.3                                                                          H    O    A                              47      CF.sub.3                                                                             F      H    H    OCF.sub.3                                                                          H    O    A                              48      CF.sub.3                                                                             H      H    H    OCF.sub.3                                                                          H    O    A                              49      CF.sub.3                                                                             NO.sub.2                                                                             H    H    OCF.sub.3                                                                          H    O    A                              50      Cl     Cl     H    H    OCF.sub.3                                                                          H    O    A                              51      CF.sub.3                                                                             Cl     H    CF.sub.3                                                                           H    F    O    A                              52      CF.sub.3                                                                             H      H    CF.sub.3                                                                           H    F    O    A                              53      CF.sub.3                                                                             F      H    CF.sub.3                                                                           H    F    O    A                              54      H      H      H    CF.sub.3                                                                           H    F    O    A                              55      Cl     F      H    H    OCF.sub.3                                                                          H    O    A                              56      Cl     F      H    CF.sub.3                                                                           H    F    O    A                              57      CF.sub.3                                                                             NO.sub.2                                                                             H    CF.sub.3                                                                           H    F    O    A                              58      Cl     Cl     H    CF.sub.3                                                                           H    F    O    A                              59      Cl     H      Cl   CF.sub.3                                                                           H    F    O    A                              60      CF.sub.3                                                                             H      CF.sub.3                                                                           CF.sub.3                                                                           H    F    O    A                              61      CF.sub.3                                                                             H      H    F    H    F    O    A                              62      CF.sub.3                                                                             F      H    F    H    F    O    A                              63      H      H      H    CF.sub.3                                                                           Cl   Cl   O    A                              64      F      H      H    CF.sub.3                                                                           Cl   Cl   O    A                              65      Cl     H      H    F    Cl   Cl   O    A                              66      CF.sub.3                                                                             F      H    H    H    Cl   O    A                              67      CF.sub.3                                                                             H      H    H    H    Cl   O    A                              68      CF.sub.3                                                                             F      H    H    H    F    O    A                              69      CF.sub.3                                                                             H      H    H    H    F    O    A                              70      CF.sub.3                                                                             F      H    H    F    CF.sub.3                                                                           O    A                              71      CF.sub.3                                                                             H      H    H    F    CF.sub.3                                                                           O    A                              72      Cl     Cl     H    H    H    F    O    A                              73      Cl     Cl     H    H    F    CF.sub.3                                                                           O    A                              74      CF.sub.3                                                                             F      H    H    F    CF.sub.3                                                                           NMe  E                              75      CF.sub.3                                                                             H      H    H    F    CF.sub.3                                                                           NMe  E                              76      CF.sub.3       H   H    F    CF.sub.3                                                                           NMe  E                              77      CF.sub.3                                                                             H      H    H    Cl   F    O    A                              78      CF.sub.3                                                                             F      H    H    Cl   F    O    A                              79      CF.sub.3                                                                             Cl     H    H    Cl   F    O    A                              80      CF.sub.3                                                                             H      H    Cl   H    Cl   O    A                              ______________________________________                                    

                  TABLE II                                                        ______________________________________                                         ##STR10##                                                                    Compound                                                                      No.      R.sub.1 R.sub.2  R.sub.3                                                                            R.sub.4                                                                              R.sub.6                                                                           R.sub.7                             ______________________________________                                        81       H       Cl       CF.sub.3                                                                           F      H   CF.sub.3                            82       H       Et       CF.sub.3                                                                           H      F   Cl                                  83       H       Et       CF.sub.3                                                                           F      H   Cl                                  84       CF.sub.3                                                                              H        CF.sub.3                                                                           F      Cl  Cl                                  85       SMe     H        CF.sub.3                                                                           F      Cl  Cl                                  86       H       NO.sub.2 CF.sub.3                                                                           F      Cl  F                                   87       H       Me       CF.sub.3                                                                           F      H   F                                   88       H       F        F    CF.sub.3                                                                             Cl  F                                   89       H       Cl       CF.sub.3                                                                           F      Cl  F                                   90       H       CN       CF.sub.3                                                                           F      Cl  F                                   91       CN      H        CF.sub.3                                                                           F      H   Cl                                  92       SO.sub.2 Me                                                                           H        CF.sub.3                                                                           F      Cl  Cl                                  93       H       Cl       CF.sub.3                                                                           F      Cl  Cl                                  94       H       F        CF.sub.3                                                                           F      F   Cl                                  95       H       Me       CF.sub.3                                                                           F      Cl  Cl                                  96       H       F        CF.sub.3                                                                           F      Cl  F                                   97       Me      H        CF.sub.3                                                                           F      Cl  Cl                                  98       H       Cl       CF.sub.3                                                                           F      Cl  Me                                  99       CN      H        CF.sub.3                                                                           F      Cl  H                                   100      NH.sub.2                                                                              H        CF.sub.3                                                                           H      Cl  Cl                                  101      NHboc   H        CF.sub.3                                                                           H      Cl  Cl                                  102      Me      H        CF.sub.3                                                                           F      Cl  H                                   103      Me      H        CF.sub.3                                                                           F      H   Cl                                  104      SMe     H        CF.sub.3                                                                           F      Cl  H                                   105      SMe     H        CF.sub.3                                                                           F      H   Cl                                  106      CF.sub.3                                                                              H        CF.sub.3                                                                           F      Cl  H                                   107      Me      H        CF.sub.3                                                                           F      Cl  Cl                                  ______________________________________                                    

                  TABLEIII                                                        ______________________________________                                         ##STR11##                                                                    Compound                                                                      No.      R.sup.1 R.sup.2 R.sup.3                                                                            R.sup.4                                                                              R.sup.6                                                                            R.sup.7                             ______________________________________                                        108      SMe     H       CF.sub.3                                                                           H      CF.sub.3                                                                           H                                   109      H       H       CF.sub.3                                                                           H      CF.sub.3                                                                           H                                   110      Cl      H       CF.sub.3                                                                           H      CF.sub.3                                                                           H                                   111      NMe.sub.2                                                                             H       CF.sub.3                                                                           H      CF.sub.3                                                                           H                                   112      H       H       CF.sub.3                                                                           F      CF.sub.3                                                                           H                                   113      SMe     H       CF.sub.3                                                                           Cl     CF.sub.3                                                                           H                                   114      SMe     H       CF.sub.3                                                                           F      H    Cl                                  115      H       H       CF.sub.3                                                                           F      H    Cl                                  116      H       H       CF.sub.3                                                                           H      H    Cl                                  117      H       H       CF.sub.3                                                                           H      CF.sub.3                                                                           H                                   118      SMe     H       CF.sub.3                                                                           H      H    Cl                                  119      SMe     H       Cl   H      H    Cl                                  120      H       H       Cl   H      H    Cl                                  121      SMe     H       CF.sub.3                                                                           Cl     H    Cl                                  122      H       H       CF.sub.3                                                                           Cl     H    Cl                                  123      CN      H       CF.sub.3                                                                           Cl     H    Cl                                  124      SMe     H       CF.sub.3                                                                           H      Cl   H                                   125      Sme     H       CF.sub.3                                                                           Cl     Cl   H                                   126      H       H       CF.sub.3                                                                           Cl     Cl   H                                   127      H       H       CF.sub.3                                                                           H      Cl   H                                   128      H       H       CF.sub.3                                                                           H      H    H                                   129      H       H       CF.sub.3                                                                           F      H    CF.sub.3                            130      H       H       CF.sub.3                                                                           F      H    H                                   131      H       Et      CF.sub.3                                                                           H      H    Cl                                  132      H       Et      CF.sub.3                                                                           F      H    Cl                                  133      H       H       CF.sub.3                                                                           NO.sub.2                                                                             H    H                                   134      H       CHO     CF.sub.3                                                                           H      H    H                                   135      H       H       F    CF.sub.3                                                                             H    F                                   136      H       H       CF.sub.3                                                                           H      H    F                                   137      H       H       F    H      H    Cl                                  138      H       H       H    CF.sub.3                                                                             H    Cl                                  139      H       H       F    F      H    Cl                                  140      H       H       NO.sub.2                                                                           H      H    Cl                                  141      H       H       CN   H      H    Cl                                  142      H       H       F    H      H    Cl                                  143      H       H       OMe  H      H    Cl                                  144      H       H       CF.sub.3                                                                           H      H    CF.sub.3                            145      H       H       CF.sub.3                                                                           Cl     H    CF.sub.3                            146      H       H       CF.sub.3                                                                           NO.sub.2                                                                             H    Cl                                  147      H       H       CF.sub.3                                                                           H      H    Me                                  148      H       H       CF.sub.3                                                                           Cl     H    Me                                  149      H       H       CF.sub.3                                                                           F      H    Me                                  150      H       H       Cl   F      H    Cl                                  151      H       H       Cl   Cl     H    Cl                                  152      H       H       CF.sub.3                                                                           H      H    OMe                                 153      H       H       CF.sub.3                                                                           F      H    OMe                                 154      H       H       CF.sub.3                                                                           H      Cl   Cl                                  155      H       H       CF.sub.3                                                                           F      Cl   Cl                                  156      H       Et      CF.sub.3                                                                           F      CF.sub.3                                                                           H                                   157      H       Et      CF.sub.3                                                                           H      CF.sub.3                                                                           H                                   158      H       Et      CF.sub.3                                                                           Cl     CF.sub.3                                                                           H                                   159      H       n-Pr    CF.sub.3                                                                           H      CF.sub.3                                                                           H                                   160      H       n-Pr    CF.sub.3                                                                           F      CF.sub.3                                                                           H                                   161      H       H       CF.sub.3                                                                           H      H    Br                                  162      H       H       CF.sub.3                                                                           F      H    Br                                  163      H       Me      CF.sub.3                                                                           H      H    H                                   ______________________________________                                    

EXAMPLE 10 Insecticidal and acaricidal evaluation of test compounds

Test solutions are prepared by dissolving the test compound in a 35%acetone in water mixture to give a concentration of 10,000 ppm.Subsequent dilutions are made with water as needed.

Spodoptera eridania, 3rd instar larvae, southern armyworm (SAW)

A Sieva lima bean leaf expanded to 7-8 cm in length is dipped in thetest solution with agitation for 3 seconds and allowed to dry in a hood.The leaf is then placed in a 100×10 mm petri dish containing a dampfilter paper on the bottom and ten 3rd instar caterpillars. At 5 days,observations are made of mortality, reduced feeding, or any interferencewith normal molting.

Diabrotica virgifera virgifera Leconte, 3rd instar western corn rootworm(WCR)

One cc of fine talc is placed in a 30 mL wide-mouth screw-top glass jar.One mL of the appropriate acetone test solution is pipetted onto thetalc so as to provide 1.25 mg of active ingredient per jar. The jars areset under a gentle air flow until the acetone is evaporated. The driedtalc is loosened, 1 cc of millet seed is added to serve as food for theinsects and 25 mL of moist soil is added to each jar. The jar is cappedand the contents thoroughly mixed mechanically. Following this, ten 3rdinstar rootworms are added to each jar and the jars are loosely cappedto allow air exchange for the larvae. The treatments are held for 5 dayswhen mortality counts are made. Missing larvae are presumed dead, sincethey decompose rapidly and can not be found. The concentrations ofactive ingredient used in this test correspond approximately to 50kg/ha.

Aphis fabae, mixed instar, bean aphid (BA)

Pots containing single nasturtium plants (Tropaeolum sp.) about 5 cmtall are infested with about 100-200 aphids one day before the test.Each pot is sprayed with the test solution for 2 revolutions of a 4 rpmturntable in a hood. The spray is directed to give complete coverage ofthe plants and aphids. The sprayed pots are set on their sides on whitetrays and held for 2 days, following which mortality estimates are made.Essentially the same method is used with respect to cotton aphid (CA).

Tetranychus urticae(OP-resistant strain), 2-spotted spider mite (TSM)

Sieva lima bean plants with primary leaves expanded to 7-8 cm areselected and cut back to one plant per pot. A small piece is cut from aninfested leaf taken from the main colony and placed on each leaf of thetest plants. This is done about 2 hours before treatment to allow themites to move over to the test plant to lay eggs. The size of the cut,infested leaf is varied to obtain about 100 mites per leaf. At the timeof test treatment, the piece of leaf used to transfer the mites isremoved and discarded. The newly-infested plants are dipped in the testsolution for 3 seconds with agitation and set in the hood to dry. After2 days, one leaf is removed and mortality counts are made.

The tests are rated according to the scale shown below and the dataobtained are shown in Table IV.

Rating Scale

A 0-45% kill

B 45-75% kill

C 76-100% kill

                  TABLE IVa                                                       ______________________________________                                        Insecticidal Activity Of Test Compounds Against Bean                          Aphid (300 ppm)                                                                     BA                 BA             BA                                          AD-                AD-            AD-                                   Com-  FOLIAR             FOLIAR         FOLIAR                                pound 300      Compound  300    Compound                                                                              300                                   Number                                                                              (ppm)    Number    (ppm)  Number  (ppm)                                 ______________________________________                                        5     A        48        B      145     B                                     9     B        49        B      147     C                                     13    C        50        B      150     B                                     15    C        53        C      151     B                                     17    C        54        C      153     B                                     18    A        55        A      154     B                                     19    A        58        C      155     C                                     20    B        59        B      156     C                                     21    A        61        C      157     B                                     22    B        62        B      161     C                                     24    A        63        A      163     A                                     25    A        71        C                                                    26    B        108       B                                                    27    B        109       B                                                    28    A        111       C                                                    29    A        128       B                                                    30    A        129       B                                                    31    B        130       A                                                    32    B        132       C                                                    33    B        135       A                                                    37    A        137       C                                                    38    A        139       C                                                    42    B        140       A                                                    43    C        141       B                                                    45    C        142       C                                                    46    B        143       C                                                    47    A        144       B                                                    ______________________________________                                    

                  TABLE IVb                                                       ______________________________________                                        Insecticidal Activity of Test Compounds against                               Southern Army Worm (1000 ppm)                                                         SAW                     SAW                                                   2.sup.ND -FOLIAR        2.sup.ND -FOLIAR                              Compound                                                                              1000          Compound  1000                                          Number  (ppm)         Number    (ppm)                                         ______________________________________                                        1       A             54        C                                             2       A             55        A                                             3       B             60        C                                             4       A             62        C                                             5       A             109       A                                             6       A             110       C                                             8       A             112       A                                             82      C             115       A                                             12      C             116       A                                             13      C             117       A                                             18      A             119       B                                             20      A             122       B                                             21      A             129       A                                             22      A             131       A                                             23      A             132       A                                             29      A             135       A                                             30      A             136       A                                             32      A             144       A                                             37      C             145       A                                             40      A             155       A                                             44      A             156       A                                             46      B             157       A                                             47      A             158       A                                             48      A             159       A                                             50      A             160       A                                             51      B             161       A                                             52      A             162       A                                             53      A                                                                     ______________________________________                                    

                  TABLE IVc                                                       ______________________________________                                        Insecticidal Activity of Test Compounds against Two-                          spotted Spider Mite (300 ppm)                                                           TSM                    TSM                                                    AD-FOLIAR              AD-FOLIAR                                    Compound  300          Compound  300                                          Number    (ppm)        Number    (ppm)                                        ______________________________________                                        2         C            64        A                                            4         A            66        A                                            5         B            67        A                                            12        C            68        B                                            15        C            70        B                                            18        A            71        A                                            21        A            78        B                                            22        A            115       B                                            23        A            116       B                                            29        B            128       C                                            30        B            132       B                                            37        A            135       A                                            38        A            136       A                                            39        A            140       B                                            41        A            142       C                                            42        C            147       C                                            43        C            150       C                                            47        B            156       B                                            48        B            157       B                                            49        B            159       B                                            54        C            160       A                                            55        A            163       B                                            63        A                                                                   ______________________________________                                    

                  TABLE IVd                                                       ______________________________________                                        Insecticidal Activity of Test Compounds against Western                       Corn Rootworm (50 ppm)                                                                  WCR                   WCR                                                     2.sup.ND -SOIL        2.sup.ND -SOIL                                Compound  50          Compound  50                                            Number    (ppm)       Number    (ppm)                                         ______________________________________                                        5         C           57        C                                             7         C           59        C                                             12        C           60        C                                             19        C           64        C                                             21        C           66        C                                             22        C           85        C                                             23        B           92        C                                             24        C           114       C                                             27        C           125       B                                             35        C           129       B                                             37        B           131       C                                             38        C           139       C                                             39        B           144       C                                             42        B           145       C                                             43        C           157       C                                             50        C           158       C                                             51        C           160       C                                             55        C           163       C                                             56        B                                                                   57        C                                                                   ______________________________________                                    

                  TABLE IVe                                                       ______________________________________                                        Insecticidal Activity of Test Compounds against Cotton                        Aphid (300 ppm)                                                                             CA-FOLIAR                                                       Compound      300                                                             Number        (ppm)                                                           ______________________________________                                        63            C                                                               64            A                                                               66            A                                                               67            C                                                               68            C                                                               71            B                                                               78            B                                                               ______________________________________                                    

What is claimed is:
 1. A compound of formula IA ##STR12## R¹ and R² each independently represents a hydrogen or halogen atom or an alkyl, alkenyl, alkinyl, alkoxy, alkoxyalkyl, alkoxyalkoxy group, alkylthio, alkylsulphinyl or alkylsulphonyl group, an amino, alkylamino or dialkylamino group or a cyano, nitro, haloalkyl, haloalkoxy, haloalkylthio or SF₅ group; A represents a phenyl group being substituted by one or more of the same or different substituents selected from halogen atoms, alkyl, alkoxy, cyano, nitro, haloalkyl, haloalkoxy, alkylthio, haloalkylthio, alkylsulphinyl, alkylsulphonyl and SF₅ groups; and B represents a phenyl group being substituted by one or more of the same or different substituents selected from halogen atoms, alkyl, alkoxy, cyano, nitro, haloalkyl, haloalkoxy, alkylthio, haloalkylthio, alkylsulphinyl, alkylsulphonyl and SF₅ groups; with the proviso that either A or B must be substituted by at least one halogen atom.
 2. The compound according to claim 1, wherein the compound is selected from the group consisting of4-(4'-chlorophenyl)-6-(4"-fluoro-3"-trifluoromethylphenyloxy)pyrimidine; and 4-(4'-chlorophenyl)-6-(3"-trifluoromethylphenyloxy)pyrimidine.
 3. A process for the preparation of a compound of formula IA according to claim 1, which comprises reacting a respective compound of the formula IIA, ##STR13## in which B, R¹ and R² are as defined in claim 1 and L¹ is a leaving group, with a compound of formula IIIA,

    A--OM.sup.1                                                (IIIA)

wherein A is as defined in claim 1; and M¹ represents a hydrogen or a metal atom.
 4. A composition for the control of insect or acarid pests which comprises an agronomically acceptable carrier and a pesticidally effective amount of a compound having the structural formula IA according to claim
 1. 5. The composition according to claim 4, comprising at least two carriers, one of which is a surface-active agent. 